Leptospirosis in Malaysia, and the water to think twice about

The US CDC lists leptospirosis on its Malaysia traveller page and describes the ways most people get sick:

• touching urine or other body fluids from an infected animal
• swimming or wading in urine-contaminated fresh water, or contact with urine-contaminated mud
• drinking water or eating food contaminated with animal urine

Its advice is two lines: avoid contaminated water and soil, and avoid floodwater.

NaTHNaC's description of the disease fills in the rest. Leptospirosis is “a bacterial infection which can infect humans and animals (most commonly rodents, cattle, pigs and dogs).” It names the activities that raise the risk — “kayaking, outdoor swimming, fishing or working with animals or animal parts” — and adds that “travellers visiting areas where flooding is a problem may also be at risk.” Person-to-person transmission is rare.

Sources: US CDC — Malaysia traveller page, read 4 October 2026; NaTHNaC — Leptospirosis (Weil's disease), published 23 November 2018, read 4 October 2026.

For a two-week visitor, leptospirosis is a reason to skip one river swim. For a resident it is a pattern of exposure that repeats.

The activities NaTHNaC names are the ordinary weekends of a long stay in Malaysia: a waterfall swim, a kayak trip, fishing, a jungle trail after rain. A visitor does each once. A resident does them for years, and the risk accumulates with every trip into fresh water.

The second exposure is not a choice at all. Both health services connect the disease to flooding, and floods put contaminated water into streets and homes rather than only rivers. Our flooding guide covers when and where Malaysia's floods happen; on this page, the point is simply that wading through floodwater is exactly what the CDC tells you not to do.

There is no human vaccine, so avoidance is the whole of the prevention: cover cuts and grazes, avoid swimming or wading in fresh water that may be contaminated, and stay out of floodwater where you can.

NaTHNaC lists the early symptoms as “a high temperature, headache, feeling nauseous and vomiting, aching muscles and joints, red eyes and loss of appetite” — easy to mistake for flu, or for dengue.

It then describes the serious form: “yellow skin and eyes (jaundice), swollen ankles, feet or hands, chest pain, shortness of breath and coughing up blood.”

Treatment, it says, “is usually with antibiotics, most people fully recover in a few days or weeks.” Over-the-counter medicines can treat fever and pain, and “more serious infection may require hospital treatment.”

The practical rule: if a fever starts in the days after fresh water or floodwater, tell the doctor about the exposure. It changes what they test for. Which treatment is right is a clinical decision for that doctor.

Leptospirosis is an infection contracted after arrival, which puts it on the ordinary side of a health policy — it is not a pre-existing condition. The cost sits in the serious cases, where admission is involved.

One exclusion deserves attention on this page in particular. The policy wording excludes a Hazardous Activity unless it was declared and accepted before you started, and what counts as hazardous is “as determined by” the insurer. Caving is specifically excluded. If kayaking, rafting or other water sports are part of your life in Malaysia, declare them when you buy rather than assume.

For remote rivers and interior trips, distance is the other risk. Evacuation cover is an optional add-on — up to US$100,000 for transfer to the nearest country with appropriate facilities — and air, sea and mountain rescue are always excluded.

Public treatment is charged at the Ministry of Health's foreigner rates — RM40 outpatient, RM120 specialist, RM100 emergency — and private hospitals charge private rates. The cover we arrange is worldwide — the United States is the one exception — and pre-existing conditions are excluded.